Flexible tubing for the conducting of hot jet engine gases

ABSTRACT

Flexible conduit for guiding exhaust gases from a jet engine, particularly for aircraft use. Said conduit is intended for attachment to the discharge end of a jet engine for redirecting the flow of propellant gases, as for either braking or attitude control purposes. The conduit in the preferred embodiment comprises a plurality of base rings pivoted to each other on alternately perpendicular axes with a flexible hose of heatresistant material provided internally of said rings and a protective skin applied externally of said ring. Preferably serially connected hydraulic means are provided between alternately pivoted pairs of rings to provide hydraulic control for pivoting or flexing said conduit as desired.

United States Patent 1191 Weigmann 1 FLEXIBLE TUBING FOR THE CONDUCTINGOF HOT JET ENGINE GASES [75] Inventor: Erich W. Weigmann, Munchen,

Germany [73] Assignee: Messerschmitt-Bolkow Blohm GmbI-I, Munich,Germany [22] Filed: May 28, 1971 [21] Appl. No.: 148,010

[30} Foreign Application Priority Data June 8, 1970 Germany P 20 28067.5

[52] US. Cl 239/265.35, 239/265.43, 239/588 [51] Int. Cl. B641! 15/04[58] Field of Search 239/265.1 1,265.33,

1451 Sept. 18,1973

Primary Examiner-Lloyd L. King Attorney-Woodhams, Blanchard & Flynn [57]ABSTRACT Flexible conduit for guiding exhaust gases from a jet engine,particularly for aircraft use. Said conduit is intended for attachmentto the discharge end of a jet engine for redirecting the flow ofpropellant gases, as for either braking or attitude control purposes.The conduit in the preferred embodiment comprises a plurality of baserings pivoted to each other on alternately perpendicular axes withaflexible hose of heat-resistant material provided internally of saidrings and a protective skin applied externally of said ring. Preferablyserially connected hydraulic means are provided between alternatelypivoted pairs of rings to provide hydraulic control for pivoting orflexing said conduit as desired.

13 Claims, 5 Drawing; Figures 1 FLEXIBLE TUBING FOR THE CONDUCTING OFHOT JET ENGINE GASES The invention refers to a flexible conduit for theguiding of hot jet engine gases, said conduit consisting of a series ofbase rings arranged in sequence in the direction of flow. The conduit isprovided with joints in such a manner that successive base rings can beangled with respect to each other. A flexible inner lining supported bythe rings is provided on the inside of the conduit and an outer skinsurrounds and is supported by said rings.

The function of such flexible conduit or pipes is to redirect the flowof propellant gases generated by the jet engine in directions other thanthe axial direction of the jet engine. The redirecting, for example, mayoccur when it is necessary to convert the propellant force of the jetengine gases to a braking force; or to generate in the propellant gasesbeing discharged at the tail of the plane a steering moment which can beutilized'for positioning corrections, etc.

Besides numerous other means suggested for dealing with these problems,flexible tubing of the above mentioned type does already exist, wherebyeach base ring may be pivoted with respect to a preceding ring by meansof joints at the side, in such a manner that all such rings, and thusthe entire piece of tubing can be moved in one plane, that is thelengthwise symmetrical plane of the jet (DAS 1 238341). An inner liningis provided and consists of conventional sheet metal rings which areconnected to the base rings, and which overlap so as to allow for agas-tight channel of flow forthe propellant gas, while maintainingmaximum flexibility in the curvature of the conduit. It is obvious thatin such a construction a great many base rings and corresponding sheetmetal rings must be provided to achieve the continuous pipe-wallnecessary to avoid a continuous loss of gases. Such a construction isunsatisfactory due both to its considerable expense and to itscumbersome nature resulting from its excessive weight. Further, thisconventional construction permits directing the jet engine gases only inthe direction of roll control of the plane.

It is the purpose of this invention to design such a conduit which willprovide for a simple loss-free channel, which will use a minimum numberof rings and which will provide for directing the jet stream in thedirection of both roll'control and yaw control.

The purpose of the inventionis achieved byallowing the rings, beginningwith a first ring which is solidly connected to the jet engine casing,to pivot with-respect to the preceding ring, alternately in horizontaland vertical planes and by having the inner lining in the form of aspiral hose made of heat-resistant material. The last ring carries thedischarge nozzle. In case of a motion in only one plane, for example, inthe lengthwise symmetrical plane of the jet, this method of constructioncauses only each second pilot ring to perform a pivoting motion withrespect to preceding ring and to carry along the immediately subsequentguide ring rigidly in the direction of the motion. However, a variety ofmotion combinations are also possible as a result of the twospecifically provided pivotal motions, whereby all of the ringscontribute a portion to the total swiveling motion.

The use of a conventionally flexible spiral hose makes it possible toutilize a relatively small number of rings, because the very nature ofthe hose allows it to assume a constant curvature even with a minimum ofsupport points. The total required number of rings naturally depends onthe required total angle of pivoting. For example, if a total pivotingangle of 30 is required, with respect to each of the pivoting planes,three pivoting rings appear to be sufficient respectively for eachpivoting plane, resulting in a total of six individual rings which worktogether in pairs.

According to one characteristic of the invention, it is intended thateach ring is so designed as to enable it to receive both the innerlining and the outer skin. In this manner, the rings stabilize the innerlining and the outer skin in an axial as well as a radial sense, so thatself-induced axial motions of these components are prevented.

For moving the flexible conduit of the invention, there is provided anadjustment apparatus which provides for the installation of controldevices between each two rings, directly acting on the same, for thepurpose of producing the respective pivoting motions. In comparison tothe conventional solutions, provided by the above mentioned DAS 1238341,in which the rings themselves are connected to a multimemberedscissors, which itself is activated by one or more positioning motors,the arrangement suggested in the present invention offers the advantagethat due to the absence of intermediary members, these possible causesfor me chanical failure are eliminated. This assures a particularlydependable and smooth functioning of all individual parts during achange in adjustment. Besides the solution'suggested by the inventionprovides an opportunity to utilize the redundancy technique which isrequired particularly in the construction of airplanes, by providingseveral adjustment and control devices.

According to an additional characteristic of the invention, alladjustment motors are double acting hydraulic cylinders, whereby theadjustment motors for movement in the horizontal plane as well as thosein the vertical plane are coupled by hydraulic means. This allows forthe installation of a single control valve in order to regulateallcylinders which generate motion in the same plane. 1

An additional embodiment of the invention provides for the coupledhydraulic adjustment motors to be connected in series in such a mannerthat the outlet of the preceding cylinder forms the input of succeedingcylinden-The hydraulic fluid expelledby the preceding cylinder in eachcase provides the hydraulic pressure for the succeeding cylinder, sothat due to the incompressibility of the fluid a uniform functioning ofall hydraulic cylinders can be achieved.

One embodiment of the invention is illustrated in the drawings, detaileddescriptions of which follow. There is shown in FIG. 1: a sideview of aconduit made of seven rings in extended position;

FIG. 2: a conduit according to FIG. 1, in a downward position;

FIG. 3: a view of the conduit, according to F IG. 1, as seen from thejet side;

I FIG. 4: a lengthwise cut through a portion of the conduit according toFIG. 1;

FIGQS: a hydraulic valving plan forthe operating devices of the conduit.

FIG. 1 shows in general a piece ofconduit which consists of sevensuccessively arranged base rings 1, an

outer skin 2 being connected to the rings, and inside of .that an innerlining 3 which in FIG. 1 is indicated only with dotted lines. The firstring shown in FIG. 1 to the extreme left is rigidly attached to thedischarge nozzle 4 of a jet engine (not illustrated). The second ring isconnected to this first ring by means of the joints 5, in such a manner,that it can pivot laterally about a vertical axis, that is, in ahorizontally pivoting motion. The second ring supports by joint 6 thethird ring which can be pivoted about a horizontal axis, that is in avertically pivoting motion.

The motion of the second ring with respect to the first one is effectedby the hydraulic cylinder 7, the cylinder casing of which is connectedto the first ring and the piston rod of which is attached to the secondring. In like manner, a hydraulic cylinder 8 is provided to effectmovement of the third ring with respect to the second, etc.

FIG. 2 shows the pipe in a downward position. The total pivot angle a iscomposed of the individual angles about which the vertically pivotablerings are pivoted with respect to the directly preceding ring. In FIG.2,

the third ring is pivoted with respect to the second ring, the fifthwith respect to the fourth, and the seventh with respect to the sixth,10 in each case, resulting in a total pivoting angle of 30. For thispurpose, only the hydraulic cylinders 8 were activated, while thehydraulic cylinders 7 remained in zero position. The pieces of outerskin 2 arranged between these rings, as well as the inner lining, whichis not shown, smooth out the joints and through their normal elasticityprovide for a smooth continuity;

FIG. 3 shows a piece of conduit according to, FIG. 1 in a view as seenfrom the jet stream pipe. To be seen are the joints between the firstand the second rings, as well as the hydraulic cylinder 7 which arenecessary for the operation of the second ring, also the joints 6 andrespective hydraulic cylinder 8.

FIG. 4 shows the construction of the outer skin 2, the inner lining 3,and their respective attachments to the rings 1. In the illustratedembodiment, the outer skin consists of individual sections which arearranged respectively between the base rings 1. The outer skin sectionsare in this fashion attached to the rings, for example by means ofrivets, in a gas-tight manner. By this arrangement it is unnecessary toattach the skin to the outside diameter of the ring, which latter wouldresult in an increased total diameter of the pipe. The inner liningconsists of a spiral hose which is made of a special heat-resistantmaterial. Because of its own respective properties of stiffness andelasticity, it assumes a smooth continuity from the straight piece ofhose to the curved piece of hose, and thereby minimizes obstructions tosmooth flow. The space remaining between outer skin and inner lining maybe used for the conducting of cooling air, so that the outer skin, aswell as the apparatus on the outside of the skin can be effectivelyprotected from heat damage.

FIG. 5 shows as an example the construction of the hydraulic controldevice for one of the two adjustment motions. The three paired,successively arranged hydraulic cylinder 8, the cylinder casings ofwhich in each case are attached to a base ring, contain in each case adually acting hydraulic piston 10, the piston rod of which is attachedto the succeeding ring (see FIG. 1 and 2). If a given piece of pipe isto be bent downward, the pistons 10 are moved to the right. A pump 11supplies hydraulic fluid to the service valve 12 which directs it to thedesired side of the piston 10. In the illustrated example, the pistonsare to be moved to the right, so that the hydraulic fluid is conductedthrough the tubing 13 to the left chamber of the first pair ofcylinders. These then, while in motion, expel the hydraulic fluidcontained in the right chambers, and conduct it through the tubing 14 tothe left chambers of the second pair of cylinders. In like manner, theleft chambers of the third pair of cylinders are activated by thehydraulic fluid being expelled by the second pair of cylinders. Thetubing 16 serves to vent air and to adjust for leakage. Because of theincompressibility of the hydraulic fluid, the system functions withoutyielding or delay. In this manner, with simple means, for example withthe aid of only one control valve 12, a uniform functioning of theentire system is made possible, as desired and intended.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A flexible conduit for the conducting of a gaseous medium,comprising:

a plurality of axially spaced base rings arranged in series so that saidgaseous medium is transmitted through the central portion of said baserings parallel to the longitudinal axes of said base rings;

first hinge means for connecting a first pair of mutually adjacent baserings and defining a fixed first hinge axis, said first hinge axis beinglocated in the axial spacing between said first pair of base rings andin a plane perpendicular to the axis of one of said first pair ofmutually adjacent base rings; and

second hinge means for connecting a second pair of mutually adjacentbase rings and defining a fixed second hinge axis, said second hingeaxis being located in the axial spacing between said second pair of baserings and in a plane perpendicular to the axis of one of said secondpair of mutually adjacent base rings.

2. A flexible conduit according to claim 1, wherein said first andsecond hinge means includes first and second coupling means,respectively, each being adapted to couple a base ring to a mutuallyadjacent base ring, said first coupling means including means definingsaid first hinge axis'thereon and said second coupling means includingmeans defining said second hinge faxis thereon, said second hinge axisbeing spaced from said first hinge axis.

3. A flexible conduit according to claim 2, wherein said first hingeaxis intersectssaid longitudinalaxes of said first pair of base ringsand wherein said second hinge axis intersects said longitudinal axes ofsaid second pair of base rings.

4. A flexible conduit according to claim 1, including means defining aninner lining and further including means defining an outer skin.

5. A flexible conduit according to claim 4, wherein said outer skinmeans comprises individual skin sections'secured to and arranged betweensaid base rings.

6. A flexible conduit according to claim 1, including first drive meansfor effecting a relative pivoting of said first pair of base rings aboutsaid first hinge axis;

second drive means for effecting a relative pivoting of said second pairof base rings about said second pivot axis; and

control means for selectively controlling said first and second drivemeans.

7. A flexible conduit according to claim 6, wherein said first andsecond drive means are each located in said axial spacing between saidfirst'and second pair of 5 mutually adjacent base rings, respectively.

8. A flexible conduit according to claim 6,wherein said first and seconddrive means are dually acting hydraulic cylinders, one end of each ofsaid cylinders being connected to one base ring and the opposite endthereof being connected to the next adjacent base ring.

9. A flexible conduit according to claim 8, wherein said control meanscomprises conduit means coupled to each of said first and second drivemeans and is adapted to cause a uniform pivoting of each ring about arespective one of said first and second hinge axes.

10. A flexible conduit according to claim 9, wherein each of said firstdrive means between difl'ering first pairs of said base rings areconnected in series so that the output from one first drive meansdefines the input for the next first drive means.

11. A flexible conduit according to claim 10, including air vent andleakage control means between each of said series connected said firstdrive means and said second drive means.

12. A flexible conduit for the conducting of a gaseous medium,comprising:

a plurality of axially spaced base rings arranged in series so that saidgaseous medium is transmitted through the central portion of said baserings parallel to the longitudinal axes of said base rings;

first hinge means defining a first hinge axis for pivotally connecting afirst pair of mutually adjacent base rings;

second hinge means defining a second hinge axis for pivotally connectinga second pair of mutually adjacent rings, said second hinge axis beingspaced axially along said series of base rings and positionedtransversely to said series of base rings and positioned transversely tosaid first hinge axis; and

securement means for securing said plurality of said base rings to arelatively fixed casing structure, said securement means being adaptedto prevent a rotation of said base rings about the longitudinal axesthereof.

13. A flexible conduit according, to claim 12, wherein said casingstructure defines the jet exhaust nozzle of a jet propelled aircraft andsaid pivoting of saidbase rings effects a control of the vectoring ofsaid aircraft.

1. A flexible conduit for the conducting of a gaseous medium,comprising: a plurality of axially spaced base rings arranged in seriesso that said gaseous medium is transmitted through the central portionof said base rings parallel to the longitudinal axes of said base rings;first hinge means for connecting a first pair of mutually adjacent baserings and defining a fixed first hinge axis, said first hinge axis beinglocated in the axial spacing between said first pair of base rings andin a plane perpendicular to the axis of one of said first pair ofmutually adjacent base rings; and second hinge means for connecting asecond pair of mutually adjacent base rings and defining a fixed secondhinge axis, said second hinge axis being located in the axial spacingbetween said second pair of base rings and in a plane perpendicular tothe axis of one of said second pair of mutually adjacent base rings. 2.A flexible conduit according to claim 1, wherein said first and secondhinge means includes first and second coupling means, respectively, eachbeing adapted to couple a base ring to a mutually adjacent base ring,said first coupling means including means defining said first hinge axisthereon and said second coupling means including means defining saidsecond hinge axis thereon, said second hinge axis being spaced 90* fromsaid first hinge axis.
 3. A flexible conduit according to claim 2,wherein said first hinge axis intersects said longitudinal axes of saidfirst pair of base rings and wherein said second hinge axis intersectssaid longitudinal axes of said second pair of base rings.
 4. A flexibleconduit according to claim 1, including means defining an inner liningand further including means defining an outer skin.
 5. A flexibleconduit according to claim 4, wherein said outer skin means comprisesindividual skin sections secured to and arranged between said baserings.
 6. A flexible conduit according to claim 1, including first drivemeans for effecting a relative pivoting of said first pair of base ringsabout said first hinge axis; second drive means for effecting a relativepivoting of said second pair of base rings about said second pivot axis;and control means for selectively controlling said first and seconddrive means.
 7. A flexible conduit according to claim 6, wherein saidfirst and second drive means are each located in said axial spacingbetween said first and second pair of mutually adjacent base rings,respectively.
 8. A flexible conduit according to claim 6, wherein saidfirst and second drive means are dually acting hydraulic cylinders, oneend of each of said cylinders being connected to one base ring and theopposite end thereof being connected to the next adjacent base ring. 9.A flexible conduit according to claim 8, wherein said control meanscomprises conduit means coupled to each of said first and second drivemeans and is adapted to cause a uniform pivoting of each ring about arespective one of said first and second hinge axes.
 10. A flexibleconduit according to claim 9, wherein each of said first drive meansbetween differing first pairs of said base rings are connected in seriesso that the output from one first drive means defines the input for thenext first drive means.
 11. A flexible conduit according to claim 10,including air vent and leakage control means between each of said seriesconnected said first drive means and said second drive means.
 12. Aflexible conduit for the conducting of a gaseous medium, comprising: aplurality of axially spaced base rings arranged in series so that saidgaseous medium is transmitted through the central portion of said baserings parallel to the longitudinal axes of said base rings; first hingemeans defining a first hinge axis for pivotally connecting a first pairof mutually adjacent base rings; second hinge means defining a secondhinge axis for pivotally connecting a second pair of mutually adjacentrings, said second hinge axis being spaced axially along said series ofbase rings and positioned transversely to said series of base rings andpositioned transversely to said first hinge axis; and securement meansfor securing said plurality of said base rings to a relatively fixedcasing structure, said securement means being adapted to prevent arotation of said base rings about the longitudinal axes thereof.
 13. Aflexible conduit according to claim 12, wherein said casing structuredefines the jet exhaust nozzle of a jet propelled aircraft and saidpivoting of said base rings effects a control of the vectoring of saidaircraft.